• Journal of the Korea Safety Management & Science
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• v.14 no.3
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• pp.229-236
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• 2012

소프트웨어 기반의 시스템 설계과정에서 설계자가 고려해야 하는 요소들이 다양해지면서 시스템 설계가 점점 어려워지고 있다. 다양한 설계 요소들이 존재하지만 사용자의 특성 및 직무, 사용가능한 정보기술의 특성 등이 핵심적인 요소로 간주된다. 또한 정보기술이 발달하면서 인간과 시스템의 상호작용이 점점 인지적인 특징을 지니게 되었다. 따라서 사용성 높고, 효율적이면서 안전한 소프트웨어 기반의 시스템을 개발하기 위해서는 시스템 설계자가 사용자의 인지적인 요구사항 및 그들의 직무를 시스템 설계과정에서 체계적으로 다룰 수 있어야 한다. 그러나 소프트웨어 공학, 시스템 공학 및 인간-컴퓨터 상호작용 등에서의 전통적인 시스템 설계 방법은 이러한 설계자의 설계활동을 효과적으로 지원하는데 한계가 있었다. 그 대안으로 인지시스템공학(cognitive systems engineering; CSE)은 인간중심의 설계철학을 바탕으로 소프트웨어 기반의 복잡한 시스템 설계과정에서 설계자의 활동을 체계적으로 도와줄 수 있는 유용한 개념과 방법을 제공해주고 있다. CSE는 원래 사람이 실시간으로 감시 및 제어해야 하는 복잡한 사회기술적 시스템(예: 원자력발전소 및 공항관제소)의 분석, 설계 및 평가를 위해 태동한 학문이다. 그러나 CSE에서 제공하는 이론적 및 방법론적 프레임워크는 소프트웨어 기반의 시스템을 설계하는 데에도 유용하게 활용할 수 있는 충분한 가능성을 갖고 있다. 이 논문은 CSE의 근간을 이루는 핵심 개념 및 원칙을 고찰하고 소프트웨어 기반 시스템 설계에의 활용가능성 및 그 방안을 논의한다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.1049-1061
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• 2013

In this paper, a relative heat exchange rate is numerically compared for cast-in-place concrete energy piles with different heat exchange pipe configurations, and a new design method for energy piles is proposed. An equivalent heat exchange rate was estimated for the W-type (one series loop), multiple U-type (four parallel loops), and coil-type heat exchanger installed in the same large-diameter drilled shaft. In order to simulate a cooling operation in summer by a CFD analysis, the LWT (leaving water temperature) into a energy pile was fixed at $35^{\circ}C$ and then the EWT (entering water temperature) into a heat pump was monitored. In case of continuously applying the artificial maximum cooling load for 100 hours, all of the three types of heat exchangers show the marginally similar heat exchange rate. However, in case of intermittently applying the cooling load with a cycle of 8 hours operation-16 hours off for 7 consecutive days, the coil type heat exchanger exhibits a heat exchange rate only 86 % of the multiple U-type due to measurable thermal interference between pipe loops in the energy pile. On the other hand, the W-type possesses the similar heat exchange rate to the multiple U-type. The equivalent heat exchange rates for each configuration of heat exchangers obtained from the CFD analysis were adopted for implementing the commercial design program (PILESIM2). Finally, a design method for cast-in-place concrete energy piles is proposed along with a design chart in consideration of typical design factors.

• Tunnel and Underground Space
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• v.32 no.2
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• pp.160-172
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• 2022

The design regulations for simple explosive storage in Korea only stipulate standards for the materials and thickness of the wall of the structure because the amount of explosives that can be stored is small. There is concern about secondary damage during an internal explosion in a simple storage facility, and it is necessary to reexamine the current standards. The numerical analysis for the TNT 15 kg explosion inside the simple storage was carried out by setting the factors using the robust experimental design method. The displacement of the structure generated under the same time condition was analyzed, and the contribution was evaluated. The contribution of concrete thickness was the highest, and the contribution of concrete strength and rebar arrangement was lower than that of concrete thickness. The reinforcement diameter contributed extremely little to the displacement. The structural standards of the simple storage that are currently applied are insufficient on blast resistance, and it is necessary to present new design standards. Therefore, the design factor to be applied later analysis and actual experiments were taken into consideration. For the design variables, the thickness of the concrete was 15 cm considering the displacement, the concrete strength was selected as general concrete considering the inlet discharge pressure, the factor with the lowest average displacement was selected for the reinforcement arrangement and the diameter of the reinforcement, the factor with the smallest level was selected in consideration of economic feasibility because the difference in displacement was low.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.1
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• pp.57-63
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• 2003

A comparative study was performed for a suspension bridge to grasp the possible differences in seismic responses evaluated by several analytical methods. The items mainly investigated are the linear vs. nonlinear response, the response spectrum method vs. the linear dynamic analysis method, and the damping ratio and it's implementation into analysis procedures. According to the numerical example, it is found that the seismic responses are considerably affected by the damping-related parameters even though slight differences are shown depending on the response quantities and the exciting directions. On the other hand, it is also confirmed that the seismic responses are less affected by the analysis method-related parameters such as the response spectrum method vs. the linear dynamic analysis method, and the linear and nonlinear analysis method. The response spectrum method is expected to give conservative results for the examined bridge, provided that the design response spectrum in the Korean Highway Design Specification is modified according to the proper damping ratio.

• Journal of Korean Society of Transportation
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• v.34 no.3
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• pp.278-290
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• 2016

Maximum traffic flow rate is an important performance measure of operational status in transport networks, and has been considered as a key parameter for transportation operation since a bottleneck in congestion decreases maximum traffic flow rate. Although previous studies for traffic flow analysis have been widely conducted, a detection method for changes in dynamic traffic flow has been still veiled. This paper explores the dynamic traffic flow detection that can be utilized for various traffic operational strategies. Turning point analysis (TPA), as a statistical method, is applied to detect the changes in traffic flow rate. In TPA, Bayesian approach is employed and vehicle arrival is assumed to follow Poisson distribution. To examine the performance of the TPA method, traffic flow data from Jayuro urban expressway were obtained and applied. We propose a novel methodology to detect turning points of dynamic traffic flow in real time using TPA. The results showed that the turning points identified in real-time detected the changes in traffic flow rate. We expect that the proposed methodology has wide application in traffic operation systems such as ramp-metering and variable lane control.

• The Journal of the Acoustical Society of Korea
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• v.39 no.3
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• pp.170-178
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• 2020

Cymbal transducers are often used as an array rather than single because they have a high quality factor and low energy conversion efficiency. When used as an array, there occurs a big change in the frequency characteristics of the array due to the interaction between constituent transducers. In this study, we designed the structure of a cymbal transducer array to have ultra-wideband characteristics using this property. First, cymbal transducers with specific center frequencies were designed. Then, a 2×2 planar array was constructed with the designed transducers, where the cymbal transducers were arranged to have same or opposite polarization directions. For this structure, we analyzed the effect of the difference in the center frequency of and the spacing between the constituent transducers on the acoustical characteristics of the array. Based on the analysis, we designed the structure of the cymbal transducer array to have the widest possible bandwidth.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.6
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• pp.459-464
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• 2013

In this paper, we introduce a modulation code design problem where best selection of two-dimensional codewords are determined to reduce two-dimensional (2D) intersymbol interference (ISI) and interpage interference (IPI). Codeword selection problem is formulated as a quadratic integer programming model that minimizes intra- and inter-symbol differences subject to uniform symbol usage and minimal Hamming distance violations. Second integer programming model detects the occurrence of isolated pixel pattern in the selected codewords. The proposed models are applied to 4-level and 2-level 6/8 codes.

• Journal of Korean Society of Transportation
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• v.23 no.5 s.83
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• pp.113-120
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• 2005

Highway geometric design aims to provide drivers with safe and efficient road conditions. Highway design method of Korea doesn't consider demand characteristics of drivers, vehicles etc. Therefore there is a gap between designer's expectation and user's behavior and it hinders to make safer roads. It is required to develop the geometric design criteria and design method based on driving characteristics to provide safe and flexible design. This study suggested a geometric design method of horizontal curves on rural 4-lane highways based on speed distribution.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.441-442
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• 2016

본 연구에서는 상용차의 무시동시 에어컨용 공진형 컨버터의 고주파 변압기 설계에 대하여 다룬다. 고주파 변압기에 적합한 코어 선정과 Area Product Ap에 의한 코어 형상 파라미터 선정법을 도출하고, 표피효과를 줄이기 위한 권선의 재질과 안정한 직류출력 전압을 얻기 위한 변압기 권선비를 제시한다. 설계된 변압기를 MAXWELL로 모델링하고 누설자속 분포를 확인한다. 공진형 컨버터에 설계된 변압기를 적용한 결과, 변압기 인덕턴스와 출력배압회로의 커패시터간의 공진이 잘 이루어짐을 확인할 수 있었다.

• Annual Conference of KIPS
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• 2018.10a
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• pp.89-92
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• 2018

QbD(Quality by Design)는 제약분야에서 혁신적 신기술로 제조공정과 품질관리를 일원화하는 방법이다. QbD는 의약품의 품질을 높은 수준으로 향상시켜 제조공정 과정을 개선하여 효율성을 증대시키고 불량률 뿐만 아니라 공정 중 불필요한 장치의 가동을 최소화하여 비용을 절감시킬 수 있다. 본 논문은 제약분야에서 QbD 적용의 필요성에 따라 에지 컴퓨팅 기반 QbD 플렛폼 설계를 제안한다. 특히, 이 QbD 플렛폼을 통해 대조약과 시험약 간의 생물학적 동등성 의약품 제조에 필요한 실험설계방법을 획기적으로 개선하고자 한다. 이를 위해 본 논문은 먼저 QbD의 단계 중 실험설계법을 제형연구의 예를 들어 설명하고 본 논문이 계획한 QbD 플랫폼의 구조를 제안한다.